A socket for an electrical interconnection typically comprises a dielectric housing having a plurality of contacts disposed in an array therein. Automatic machines for stitching the contacts into apertures of the housing are well-known. Typically, such machines have a reciprocating insertion tool which successively inserts, or stitches, contacts into the housing as the housing is incrementally indexed past the reciprocating tool.
Plastic Leaded Chip Carrier (PLCC) sockets such as those sold by AMP Incorporated of Harrisburg, Pa. under part number 821977-1 comprise a rectangular plastic housing having contacts stitched in a row along each of its four sides. In order to stitch the contacts into the housing in an automatic stitching machine, the machine must move the housing to present each of the four sides successively to the insertion tool. One method of accomplishing this would be to nest the housing in a plane perpendicular to a reciprocation axis of the tool and to translate the housing in respective x- and y-directions so that an intersection of the reciprocation axis with the housing delineates a rectangular path along the sides of the housing. This method has the disadvantage that incremental indexing of the housing must be provided in both the x- and y-directions, thereby requiring two separate indexing mechanisms with attendant complexity and expense.
Another method of presenting the four sides of the housing successively to the insertion tool with the housing nested as above-described is to alternately translate a side of the housing past the insertion tool and then to rotate the housing ninety degrees whereupon a next side of the housing is translated past the insertion tool, and so on for all four sides. This method requires only one mechanism to incrementally index housing in the x-direction. Rotation of the housing can be accomplished by a motorized drive connected to rotate the nest, but this requires a motor controller or clutch to index the rotation at quarter turn intervals, and such a system is relatively complex and expensive. Alternatively, rotation can be accomplished by providing a pawl which presents an obstruction to linear movement of the housing and nest, thereby causing the housing and nest to ride up over the pawl in a rotary motion. This arrangement suffers from the drawback that rotation can only occur where a pawl is located along the path of the housing, and multiple pawls must be spaced a minimum distance apart. Further, the nest experiences an impact each time it strikes the pawl, and this limits the speed at which motion can occur. There is a need for a different rotation mechanism which is simple, effective, and versatile, which enables rotation of the nest anywhere along its path in selectable angular increments.